During the period from January to May 1994, the prevalence of antibodies to hepatitis A virus infection (anti-HAV) was tested by immunoenzyme assay in the serum samples of 620 apparently healthy subjects (81% males, 19% females), from 10 to 29 years old, resident in North-East Italy (Pordenone and surrounding district). The overall prevalence of anti-HAV was 3.7%. There was a significant lower prevalence in the group aged 10-19 than in the one aged 20-29 years (0.7% vs 6%; p < 0.001). Moreover, a significant sex difference was observed for the 20-29 year age group (p < 0.001). Among the various risk factors considered, family size and travelling abroad to endemic areas were significantly associated with HAV infection. Since a valid and effective vaccine against HAV infection has recently become available, anti- HAV vaccination campaigns can feasibly be programmed. However, different geographical regions present different epidemiological situations, so its use should be adapted to each region, with special attention to the cost- effectiveness of the immunization programme. Our data suggest that in our region such vaccination could initially be proposed to high-risk subjects such as those travelling to endemic areas.